It seems like every time that I use a new plug-in from FabFilter, I find myself ceasing to use another similar plug-in that'd I'd been religiously using for years. Such was the case again with FabFilter ProMB; a multiband compressor/expander that, like most FabFilter plug-ins, re-invents familiar processing tools in a creative and musical way.
Perhaps the most intriguing feature of ProMB is the utilization of "dynamic phase" processing - FabFilter's innovative way of producing ultra-transparent crossover points. I've long been a fan of using multiband compressors on a drum bus to clamp down on unruly high-mids, or on a vocal track to control muddy low-mids, but I've always been dissatisfied with phase issues that can arise at crossover points. For an extreme example, a recent mix project contained 50 tracks of sampled audio from different sources, and getting the sounds to be friendly with one another required multi-band compression on almost every track. Even if I wasn't compressing with all of the bands, I would find myself adjusting the gain of a particular band instead of adding an additional EQ. While not sonically ideal, this was the most time and DSP-efficient way of producing the necessary results. ProMB allowed me to tailor the sounds into compliancy without compromising their integrity. In the past, as someone who isn't interested in manually setting the best crossover points for each band of each track for 50 tracks, I would notice, obviously, that my mix was often lacking where the default crossover points were placed. With ProMB, you begin with no bands, and only insert bands as you need them. As you place your bands, holding down the mouse button auditions said band, allowing you to zero-in on the problem frequency as you place the band. The result is typically fewer bands - exactly where you need them- and guilt-free crossover points.
Another great feature is the wet/dry knob, which in addition to traditional 0-100% blending, can go up to 200%. Yes, 200%. At first glance, this seems unnecessary, but it can yield some really interesting and musical results. Conveniently, ProMB makes it easy to keep a sonic point of reference with a handy A/B mode, allowing you to switch between two separate instances of the plug-in for comparison's sake.
Like most of FabFilter's plug-ins, there are a few features that you didn't even know you wanted, but now can't live without. One of which is mid-side multiband compression. With the aforementioned mix project, one of the clips of sampled audio had an obnoxious hi-hat in the left channel, but the middle of the image contained the vocals, which were obviously critical to the song. Mid-side EQ wasn't an option because sacrificing 1-5 kHz for the duration of the sample affected the vocals too noticeably, but ProMB allowed me to squash those pesky frequencies only when necessary. I was audibly laughing in front of the client when I heard the results.
There are many more features that add to the flexibility and power of this plug-in, including macros to simultaneously turn up the input gain while turning down the output gain, the ability to side-chain a particular band to another frequency region within the track, an optional 20 ms look-ahead, and up to four-times linear-phase oversampling for transparency during aggressive compression settings. The folks at FabFilter have raised the bar again.